I use OrchidWiz Journal to log most of this stuff.
But before that I used an excel spread sheet.
Mostly, you put stuff that matters to you.
I had:
1. name-
2. flower-(date/season it last flowered OR when it should flower "Spring" or "Autumn")
3. rest-(when and 2mon or 4 mon or none etc)
4. light-how much? I use candles (3000-4000 etc)
5. GH-meaning where in the greenhouse Warm/Interm/Cool is best for this plant
6. Day temp- max day temp
7. Nite temp- max nite temp
8. Water- any specifics here like "keep dry during rest" or "do not let media dry completely"
9. Fertilize- again specifics like "do not fertilize over winter"
10. Media- what it's potted in
11. Repot- when it was last potted
12. VT- date of last virus test and result
13. Famous- this is just my little "fun" thing where I will list a few of the famous cultivars so I can keep an eye out for them ^.^
14. Lately, I have been also adding the cost of the plant in the hopes of making myself more sensible...unfortunately, there is NO holding ME back
I have also seen flower color, fragrance, and awards but I personally don't do this...
For my plant labels, I use the name and the growing data listed in the table from items 1-9 and laminate...they are about the size of a credit card. I hole punch them AND the plastic pot and secure with a rubberband